305 56(2005)4, 305-314 UDC 629.5.023:62-419.5 Pentti KUJALA Alan KLANAC Steel Sandwich Panels in Marine Applications Preliminary communication Steel sandwich panels welded by laser can offer 30-50 % weight savings compared to the conventional steel structures. Helsinki University of Technology/Ship Laboratory has done active research during the past 10 years on various topics related to the laser welded steel sandwich panels. The work carried out includes development of design formulations for the ultimate and impact strength, analysis of fatigue strength for the joints, and development of solutions to improve the behaviour under fire. A number of research projects both at the national and European level have been ongoing. In the paper, a summary of the marine applications, main benefits and prob- lem areas of the panels as well as available design tools are given. A case study for weight and cost optimisation of a hoistable cardeck is also presented proving some of the described benefits of all steel sandwich panels. Keywords: design optimisation, hoistable cardeck, laser welding, shipbuilding structures, steel sandwich panels Primjena ËeliËnih sendviË panela u brodogradnji Prethodno priopÊenje Laserski zavareni ËeliËni sendviË paneli mogu pruæiti 30-50 % uπtede u teæini u odnosu na kovencionalne ËeliËne konstrukcije. Helsinki University of Technology/Ship Laboratory je tijekom proteklih 10 godina obavio aktivno istraæivanje razliËitih tema vezanih za laserski zavarene ËeliËne sendviË panele. Obavljena istraæivanja ukljuËuju razvijanje projektnih formula za maksimalnu i udarnu ËvrstoÊu, analizu zamorne ËvrstoÊe spojeva te razvijanje rjeπenja u svrhu poboljπanja ponaπanja panela izloæenog vatri. Postoji niz projekata na nacionalnoj i europskoj razini koji se bave ovom problematikom. U ovom radu daje se saæeti prikaz primjene ËeliËnih sendviË panela u brodogradnji, njihove osnovne prednosti, problemi vezani uz njihovu primjenu te rasploæivi projektni alati. Prikazana je i analiza sluËaja optimiziranja teæine i troπkova podizive palube za vozila koja potvruje neke od opisanih prednosti svih ËeliËnih sendviË panela. KljuËne rijeËi: optimizacija projekta podiziva paluba za vozila, lasersko zavarivanje, brodogra- evne konstrukcije, ËeliËni sendviË paneli Authors’ address (Adresa autora): Ship Laboratory, Helsinki University of Technology Espoo, Finland Received (Primljeno): 2005-04-20 Accepted (PrihvaÊeno): 2005-05-05 1 Introduction Proposals for the construction of sandwich-like components were made in different industrial branches as early as the 1950’s. However, the application of laser welding started to be increa- singly discussed only after the high power laser sources became available on the market at more affordable prices. Due to its high energy intensity resulting in a low heat input and a deep penetra- tion effect, laser welding offers a number of benefits for the production of all-metal and hybrid-metal sandwich panels. High pre-fabrication accuracy of the components, high welding speed and the possibility to connect internal stiffeners with the face sheets from outside have led to a wide application of laser welding in the construction of metal sandwich panels. In the 1980s the United States Navy led the development of laser welded sandwich panels with a robot system at the Navy Joining Centre at Pennsylvania State University. The development resulted in some prototype panels, first strength tests [1], [2], [3] and first limited applications, such as antenna platforms on the US Navy ships [4]. Between the late 1980’s and early 90’s Europe took over the lead in research related to laser welded sandwich panels. Research was initiated especially in Britain, Germany and Finland. In Britain the strength of spot welded steel sandwich panels was studied by the School of Civil Engineering at the University of Manchester [5], [6], [7]. They performed both theoretical and experimental investigations on the behaviour of steel sandwich panels under various loading and boundary conditions. Mecha- nical properties of adhesively bonded steel sandwich panels were investigated in [8] and [9]. A large German project [10] conducted by Meyer Werft between 1994 and 1999 investigated both the production and application of sandwich panels in cruise vessels. This led to the development of the I-Core panels [11]. In Finland the research related to all steel sandwich panels was initiated in 1988 in the Ship Laboratory of Helsinki Uni- versity of Technology. The first study focused on the application of sandwich panels in the shell structures of an icebreaker. Since then a considerable number of research projects in Finland, such as Shipyard 2000, Weld 2000 and Kenno – Light Structures
Steel Sandwich Panels in Marine Applications
Jun 24, 2023
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